Loud Knocking Xantia 1.9td Lexia fault update - SUCCESS

Unread post by **Peter.N.** » 04 Sep 2010, 18:56

That's fair enough, its unlikely to have changed its position, but I'm just wondering if the internal advance has stuck in the advanced position, never heard of it happening but its always a possibility. Anyway, I would think the route to go would be check the cambelt first - and then start wondering again

Did you try disconnecting the return pipe to see if there was any back pressure?

Peter

shaunlfc1 · Unread post by **shaunlfc1** » 04 Sep 2010, 19:16

I have'nt no but which return pipe are we talking about?

Should there be back pressure?

Cheers...........

Unread post by **Peter.N.** » 04 Sep 2010, 19:32

The return pipe from the pump to the tank, if it has back pressure it will upset the functioning of the pump. If you disconnect it and run the engine briefly you shouldn't lose to much fuel in the time it takes you to listen.

cachaciero · Unread post by **cachaciero** » 04 Sep 2010, 20:15

Sorry Shaun didn't get round to going on line last night and been out all today.

Clarification of Lexia session:

When we finally managed to get the Lexia to talk to the ECU it showed several error messages all temporary and all appearing to be in areas where Shaun had been previously. I cleared these and then we started the engine which started and ran ok but sounded orrible

, definitely over advanced.
The diagnostic page now showed just one error "Adjustment of Motion" together with related parameters coolant temp 20 deg and Count 40.

Now I am not sure what adjustment of motion really means but timing seems most likely. 20 deg coolant temp seemed reasonable given the conditions at the time and even if there was a failure of this sensor I can't see it advancing the engine to the degree it appeared to be but I could be wrong.

Count 40 ? havn't got a clue to what this refers to but I wonder if it is a measure of time between the crankshaft sensor and the lift needle as it seems to me that the only way the system has of verifying timing is by measuring the relationship between these two parameters.

There seemed little point in running the engine any longer than was necessary and I didn't bother looking at the parameters given that the only fault listed was that of timing and that apart from this the engine appeared to be running fine.

There was no posted failure of any of the sensors so my logic says if the sensors are good and there is a timing problem either the pump is timed incorrectly or the governor in the pump is shot i.e a broken spring.

Seem to re-call seeing a photo sequence of replacing the springs in a bosch pump somewhere recently.

cachaciero

shaunlfc1 · Unread post by **shaunlfc1** » 22 Oct 2010, 13:23

Hi all,

Its been a while but I have a little update on my problem with the Xantia. I've kind of given up on her and its been parked in the work car park now for over a month, but finally got some colleagues to come out and look at it.

Basically the pump is almost spot on 0.563mm - Haynes specifies 0.57mm no.4 at TDC.

On Tuesday we fired her up and the belt through a small gap in the cover seem to be flapping as it went from the cam sprocket and the fuel pump which is the longest section of the belt.

So yesterday I took the covers off and the belt is obviously old and according to my colleagues does seem loose, so basically the only thing I have not tried and the only thing left that could be casuing this noise is that the belt is too loose and causing the fuel pump to rock or have back lash as it try's to take up the slack causing the advance fuel injection?

Not sure that comes across that accurate - apologies!

Is this something anyone else has experienced?

Cheers again!

Unread post by **Peter.N.** » 22 Oct 2010, 14:10

Never experienced that but if the belt is very slack it could cause a variation in timing but I wouldn't have thought enough to give your symptoms. Did you try running it with the pump return pipe disconnected, this is the only other large pipe and probably also goes to the injector leak off connections, it will spew fuel out but you only have to run it long enough to hear the engine.

Peter

shaunlfc1 · Unread post by **shaunlfc1** » 25 Oct 2010, 12:59

The return pipe is this the pipe which has the hand priming pump/balloon on it?

Have not quite finished retensioning belt, but it definitely needs a new one and tensioner I think.

Its the first time I've done this, is there any major tricks to getting the tensioner out? It seems like a right pig?

Cheers all....

Unread post by **Peter.N.** » 25 Oct 2010, 14:04

No, its the other end of the pump, follow the pipe from the filter to the pump - its not that one but the other one of similar size coming from the pump, can't remember exactly where it is but I'm sure someone else can.

Peter

shaunlfc1 · Unread post by **shaunlfc1** » 25 Oct 2010, 15:40

Cheers Peter, if the checking of the timing and retensioning/new belt doesnt cure it I will definitely check out the back pressure.

Back to the timing, from out initial investigation Friday night by pegging the cam, fuel pump sprockets and when we tried to put the peg into the flywheel we could nt find it, so took the belt off and barred over the engine until location of the hole was obtained. This would suggest the crank is out of timing with the cam and fuel pump.

If this is the case, which personally I dont think it has happened, would this not cause major damage to the engine rather then simply making the pump advanced?

Thanks again.....

jgra1 · Unread post by **jgra1** » 25 Oct 2010, 16:27

I think Shaun, that it's not always the case the cam/pump being out of time with crank would automatically cause interferance.. I cant quite work it out in my head ..

how much did you have to turn the crank to get realignment on all 3?

John

edit : I had a 309 TD once that was a tooth out.. it ran! although I cant remember which of the three was out.. so not mcuh use ...

Unread post by **Peter.N.** » 25 Oct 2010, 17:57

It depends how far out it is, one tooth will upset the timing but not necessaraly cause a collision, this is only the cam timing of course, the pump timing can be anywhere, it just won't run - or knock

You can find the flywheel locking hole using a wire coat hanger bent into the shape of a starting handle (if you remember one of those) slid along the back of the starter.

Peter

shaunlfc1 · Unread post by **shaunlfc1** » 26 Oct 2010, 12:56

SUCCESS!!

I could not be happier at the moment. Although I wished I'd checked the timing belt right at the beginning!

Today I've retensioned belt, fired her up and have no noise, no K light, and she purrs like she did before this all happened!!

So all I have to do now is put a new cambelt on with new tensioner, put her back to a road worthy condition and we're away!

I'd like to thank everyone for all their help and advice as its been invaluable. Especially Tony for giving up his time to provide me with his Lexia!

So add that to the list of possible causes of advanced timing - a slack timing belt !

Thanks again,

Shaun

Unread post by **Peter.N.** » 26 Oct 2010, 12:57

Well done!

jgra1 · Unread post by **jgra1** » 26 Oct 2010, 14:56

good stuff Shaun

for my sins I am working on a Mundano at the moment, ran ok with the old belt on (for testing)

New belt, new tensioner and revised tension, and guess what, the thing is not as happy and the camshaft sprocket is slightly out of alignment by half a tooth..

did not have time to adjust this last time I was there, so will go on Sat and hopefully finish her off..

Unread post by **CitroJim** » 26 Oct 2010, 17:27

Well done Shaun, excellent news and one for archives. A loose belt is not the first thing to think of in case of a fault like this...